142 Mesozoic Floras of the Rocky Mountains. 



The present paper referred more particular by to a remarkable 

 Jurasso-cretaceous flora, recently discovered by Dr. G. M. Daw- 

 son in the Rocky Mountains, and to intermediate groups of plants, 

 between this and the middle Cretaceous, serving to extend greatly 

 our knowledge of the lower Crel aceous flora, and to render more 

 complete the series of plants between this and the Laramie. 



The oldest of these floras is found in beds which it is proposed 

 to call the Kootanie group, from a tribe of Indians of that name 

 who hunted over that part of the Rocky Mountains between the 

 49th and 52nd parallels. Plants of this age have been found on 

 the branches of the Old Man River, on the Martin Creek, at Coal 

 Creek, and at one locality far to the northwest on the Suskwa 

 River. The containing rocks are sandstones, shales and conglom- 

 erates, with seams of coal, in some places anthracitic. They 

 may be traced for 140 miles in the north and south direction, and 

 form troughs included in the Palaeozoic formation of the moun- 

 tains. The plants found are conifers, cycads and ferns, the 

 cycads being especially abundant and belonging to the genera 

 Dioonites, Zamites, Podozamites and Anomozamites. Some of 

 these cycadaceous plants as well as of the conifers, are identical 

 with species described by Heer from the Jurassic of Siberia, 

 while others occur in the lower Cretaceous of Greenland. The 

 almost world-wide Podozamites lanceolatus is very characteristic, 

 and there are leaves of Salisburya sibirica, a Siberian mesozoic 

 species, and branches of Sequoia smittiana, a species char- 

 acteristic of the lower Cretaceous of Greenland. No dicoty- 

 ledonous leaves have been found in these beds, whose plants 

 connect in a remarkable way the extinct floras of Asia and Amer- 

 ica and these of the Jurassic and Cretaceous periods. 



Above these are beds which, with some of the previous species, 

 contain a few dicotyledonous leaves, which may be provisionally 

 referred to the genera, Stercidia and Laurus ; and still higher the 

 formation abounds in remains of dicotyledonous plants of which 

 additional collections have been made by Mr. T. C. Weston. 

 The beds containing these, though probably divisible into two, 

 groups, may be named the Mill Creek series, and are approxi- 

 mately on the horizon of the Dakota group of the United States 

 geologists, as illustrated by Lesquereux and others. The species 

 are described in the paper, and differ for the most part from those 



